package org.g4studio.core.mvc.xstruts.config;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.g4studio.core.mvc.xstruts.Globals;
import org.g4studio.core.mvc.xstruts.action.ActionForm;
import org.g4studio.core.mvc.xstruts.action.ActionFormBean;
import org.g4studio.core.mvc.xstruts.action.ActionForward;
import org.g4studio.core.mvc.xstruts.action.ActionMapping;
import org.g4studio.core.mvc.xstruts.action.ActionMessages;
import org.g4studio.core.mvc.xstruts.upload.MultipartRequestWrapper;
import org.g4studio.core.mvc.xstruts.util.MessageResources;
import org.g4studio.core.mvc.xstruts.util.RequestUtils;

/**
 * <p>
 * NOTE: THIS CLASS IS UNDER ACTIVE DEVELOPMENT. THE CURRENT CODE IS WRITTEN FOR
 * CLARITY NOT EFFICIENCY. NOT EVERY API FUNCTION HAS BEEN IMPLEMENTED YET.
 * </p>
 * <p>
 * A helper object to expose the Struts shared resources, which are be stored in
 * the application, session, or request contexts, as appropriate.
 * </p>
 * <p>
 * An instance should be created for each request processed. The methods which
 * return resources from the request or session contexts are not thread-safe.
 * </p>
 * <p>
 * Provided for use by other servlets in the application so they can easily
 * access the Struts shared resources.
 * </p>
 * <p>
 * The resources are stored under attributes in the application, session, or
 * request contexts.
 * </p>
 * <p>
 * The ActionConfig methods simply return the resources from under the context
 * and key used by the Struts ActionServlet when the resources are created.
 * </p>
 * 
 * @version $Rev: 421119 $ $Date: 2005-05-14 02:09:06 -0400 (Sat, 14 May 2005) $
 * @since Struts 1.1
 */
public class ConfigHelper implements ConfigHelperInterface {
	// -------------------------------------------------------- Properites

	/**
	 * <p>
	 * The application associated with this instance.
	 * </p>
	 */
	private ServletContext application = null;

	/**
	 * <p>
	 * The session associated with this instance.
	 * </p>
	 */
	private HttpSession session = null;

	/**
	 * <p>
	 * The request associated with this instance.
	 * </p>
	 */
	private HttpServletRequest request = null;

	/**
	 * <p>
	 * The response associated with this instance.
	 * </p>
	 */
	private HttpServletResponse response = null;

	/**
	 * <p>
	 * The forward associated with this instance.
	 * </p>
	 */
	private ActionForward forward = null;

	public ConfigHelper() {
		super();
	}

	public ConfigHelper(ServletContext application, HttpServletRequest request, HttpServletResponse response) {
		super();
		this.setResources(application, request, response);
	}

	/**
	 * <p>
	 * Set the application associated with this instance.
	 * [servlet.getServletContext()]
	 * </p>
	 */
	public void setApplication(ServletContext application) {
		this.application = application;
	}

	/**
	 * <p>
	 * Set the session associated with this instance.
	 * </p>
	 */
	public void setSession(HttpSession session) {
		this.session = session;
	}

	/**
	 * <p>
	 * Set the request associated with this object. Session object is also set
	 * or cleared.
	 * </p>
	 */
	public void setRequest(HttpServletRequest request) {
		this.request = request;

		if (this.request == null) {
			setSession(null);
		} else {
			setSession(this.request.getSession());
		}
	}

	/**
	 * <p>
	 * Set the response associated with this isntance. Session object is also
	 * set or cleared.
	 * </p>
	 */
	public void setResponse(HttpServletResponse response) {
		this.response = response;
	}

	/**
	 * Set the forward associated with this instance.
	 */
	public void setForward(ActionForward forward) {
		this.forward = forward;
	}

	/**
	 * <p>
	 * Set the application and request for this object instance. The
	 * ServletContext can be set by any servlet in the application. The request
	 * should be the instant request. Most of the other methods retrieve their
	 * own objects by reference to the application, request, or session
	 * attributes. Do not call other methods without setting these first! This
	 * is also called by the convenience constructor.
	 * </p>
	 * 
	 * @param application
	 *            - The associated ServletContext.
	 * @param request
	 *            - The associated HTTP request.
	 * @param response
	 *            - The associated HTTP response.
	 */
	public void setResources(ServletContext application, HttpServletRequest request, HttpServletResponse response) {
		setApplication(application);
		setRequest(request);
		setResponse(response);
	}

	// ------------------------------------------------ Application Context
	public ActionMessages getActionMessages() {
		if (this.application == null) {
			return null;
		}

		return (ActionMessages) this.application.getAttribute(Globals.MESSAGE_KEY);
	}

	/**
	 * <p>
	 * The application resources for this application.
	 * </p>
	 */
	public MessageResources getMessageResources() {
		if (this.application == null) {
			return null;
		}

		return (MessageResources) this.application.getAttribute(Globals.MESSAGES_KEY);
	}

	/**
	 * <p>
	 * The path-mapped pattern (<code>/action/*</code>) or extension mapped
	 * pattern ((<code>*.do</code>) used to determine our Action URIs in this
	 * application.
	 * </p>
	 */
	public String getServletMapping() {
		if (this.application == null) {
			return null;
		}

		return (String) this.application.getAttribute(Globals.SERVLET_KEY);
	}

	// ---------------------------------------------------- Session Context

	/**
	 * <p>
	 * The transaction token stored in this session, if it is used.
	 * </p>
	 */
	public String getToken() {
		if (this.session == null) {
			return null;
		}

		return (String) session.getAttribute(Globals.TRANSACTION_TOKEN_KEY);
	}

	// ---------------------------------------------------- Request Context

	/**
	 * <p>
	 * The runtime JspException that may be been thrown by a Struts tag
	 * extension, or compatible presentation extension, and placed in the
	 * request.
	 * </p>
	 */
	public Throwable getException() {
		if (this.request == null) {
			return null;
		}

		return (Throwable) this.request.getAttribute(Globals.EXCEPTION_KEY);
	}

	/**
	 * <p>
	 * The multipart object for this request.
	 * </p>
	 */
	public MultipartRequestWrapper getMultipartRequestWrapper() {
		if (this.request == null) {
			return null;
		}

		return (MultipartRequestWrapper) this.request.getAttribute(Globals.MULTIPART_KEY);
	}

	public ActionMapping getMapping() {
		if (this.request == null) {
			return null;
		}

		return (ActionMapping) this.request.getAttribute(Globals.MAPPING_KEY);
	}

	// ---------------------------------------------------- Utility Methods

	/**
	 * <p>
	 * Return true if a message string for the specified message key is present
	 * for the user's Locale.
	 * </p>
	 * 
	 * @param key
	 *            Message key
	 */
	public boolean isMessage(String key) {
		// Look up the requested MessageResources
		MessageResources resources = getMessageResources();

		if (resources == null) {
			return false;
		}

		// Return the requested message presence indicator
		return resources.isPresent(RequestUtils.getUserLocale(request, null), key);
	}

	/*
	 * <p> Retrieve and return the <code>ActionForm</code> bean associated with
	 * this mapping, creating and stashing one if necessary. If there is no form
	 * bean associated with this mapping, return <code>null</code>. </p>
	 */
	public ActionForm getActionForm() {
		// Is there a mapping associated with this request?
		ActionMapping mapping = getMapping();

		if (mapping == null) {
			return (null);
		}

		// Is there a form bean associated with this mapping?
		String attribute = mapping.getAttribute();

		if (attribute == null) {
			return (null);
		}

		// Look up the existing form bean, if any
		ActionForm instance;

		if ("request".equals(mapping.getScope())) {
			instance = (ActionForm) this.request.getAttribute(attribute);
		} else {
			instance = (ActionForm) this.session.getAttribute(attribute);
		}

		return instance;
	}

	/**
	 * <p>
	 * Return the form bean definition associated with the specified logical
	 * name, if any; otherwise return <code>null</code>.
	 * </p>
	 * 
	 * @param name
	 *            Logical name of the requested form bean definition
	 */
	public ActionFormBean getFormBean(String name) {
		return null;
	}

	/**
	 * <p>
	 * Return the forwarding associated with the specified logical name, if any;
	 * otherwise return <code>null</code>.
	 * </p>
	 * 
	 * @param name
	 *            Logical name of the requested forwarding
	 */
	public ActionForward getActionForward(String name) {
		return null;
	}

	/**
	 * <p>
	 * Return the mapping associated with the specified request path, if any;
	 * otherwise return <code>null</code>.
	 * </p>
	 * 
	 * @param path
	 *            Request path for which a mapping is requested
	 */
	public ActionMapping getActionMapping(String path) {
		return null;
	}

	/**
	 * <p>
	 * Return the form action converted into an action mapping path. The value
	 * of the <code>action</code> property is manipulated as follows in
	 * computing the name of the requested mapping:
	 * </p>
	 * 
	 * <ul>
	 * 
	 * <li>Any filename extension is removed (on the theory that extension
	 * mapping is being used to select the controller servlet).</li>
	 * 
	 * <li>If the resulting value does not start with a slash, then a slash is
	 * prepended.</li>
	 * 
	 * </ul>
	 */
	public String getActionMappingName(String action) {
		String value = action;
		int question = action.indexOf("?");

		if (question >= 0) {
			value = value.substring(0, question);
		}

		int slash = value.lastIndexOf("/");
		int period = value.lastIndexOf(".");

		if ((period >= 0) && (period > slash)) {
			value = value.substring(0, period);
		}

		if (value.startsWith("/")) {
			return (value);
		} else {
			return ("/" + value);
		}
	}

	/**
	 * <p>
	 * Return the form action converted into a server-relative URL.
	 * </p>
	 */
	public String getActionMappingURL(String action) {
		StringBuffer value = new StringBuffer(this.request.getContextPath());

		// Use our servlet mapping, if one is specified
		String servletMapping = getServletMapping();

		if (servletMapping != null) {
			String queryString = null;
			int question = action.indexOf("?");

			if (question >= 0) {
				queryString = action.substring(question);
			}

			String actionMapping = getActionMappingName(action);

			if (servletMapping.startsWith("*.")) {
				value.append(actionMapping);
				value.append(servletMapping.substring(1));
			} else if (servletMapping.endsWith("/*")) {
				value.append(servletMapping.substring(0, servletMapping.length() - 2));
				value.append(actionMapping);
			}

			if (queryString != null) {
				value.append(queryString);
			}
		}
		// Otherwise, assume extension mapping is in use and extension is
		// already included in the action property
		else {
			if (!action.startsWith("/")) {
				value.append("/");
			}

			value.append(action);
		}

		// Return the completed value
		return (value.toString());
	}

	/**
	 * <p>
	 * Return the url encoded to maintain the user session, if any.
	 * </p>
	 */
	public String getEncodeURL(String url) {
		if ((session != null) && (response != null)) {
			boolean redirect = false;

			if (forward != null) {
				redirect = forward.getRedirect();
			}

			if (redirect) {
				return response.encodeRedirectURL(url);
			} else {
				return response.encodeURL(url);
			}
		} else {
			return (url);
		}
	}

	// ------------------------------------------------ Presentation API

	/**
	 * <p>
	 * Renders the reference for a HTML <base> element
	 * </p>
	 */
	public String getOrigRef() {
		// HttpServletRequest request =
		// (HttpServletRequest)pageContext.getRequest();
		if (request == null) {
			return null;
		}

		StringBuffer result = RequestUtils.requestToServerUriStringBuffer(request);

		return result.toString();
	}

	/**
	 * <p>
	 * Renders the reference for a HTML <base> element.
	 * </p>
	 */
	public String getBaseRef() {
		if (request == null) {
			return null;
		}

		StringBuffer result = RequestUtils.requestToServerStringBuffer(request);
		String path;

		if (forward == null) {
			path = request.getRequestURI();
		} else {
			path = request.getContextPath() + forward.getPath();
		}

		result.append(path);

		return result.toString();
	}

	/**
	 * <p>
	 * Return the path for the specified forward, otherwise return
	 * <code>null</code>.
	 * </p>
	 * 
	 * @param name
	 *            Name given to local or global forward.
	 */
	public String getLink(String name) {
		ActionForward forward = getActionForward(name);

		if (forward == null) {
			return null;
		}

		StringBuffer path = new StringBuffer(this.request.getContextPath());

		path.append(forward.getPath());

		// :TODO: What about runtime parameters?
		return getEncodeURL(path.toString());
	}

	/**
	 * <p>
	 * Return the localized message for the specified key, otherwise return
	 * <code>null</code>.
	 * </p>
	 * 
	 * @param key
	 *            Message key
	 */
	public String getMessage(String key) {
		MessageResources resources = getMessageResources();

		if (resources == null) {
			return null;
		}

		return resources.getMessage(RequestUtils.getUserLocale(request, null), key);
	}

	/**
	 * <p>
	 * Look up and return a message string, based on the specified parameters.
	 * </p>
	 * 
	 * @param key
	 *            Message key to be looked up and returned
	 * @param args
	 *            Replacement parameters for this message
	 */
	public String getMessage(String key, Object[] args) {
		MessageResources resources = getMessageResources();

		if (resources == null) {
			return null;
		}

		// Return the requested message
		if (args == null) {
			return resources.getMessage(RequestUtils.getUserLocale(request, null), key);
		} else {
			return resources.getMessage(RequestUtils.getUserLocale(request, null), key, args);
		}
	}

	/**
	 * <p>
	 * Return the URL for the specified ActionMapping, otherwise return
	 * <code>null</code>.
	 * </p>
	 * 
	 * @param path
	 *            Name given to local or global forward.
	 */
	public String getAction(String path) {
		return getEncodeURL(getActionMappingURL(path));
	}

	// --------------------------------------------- Presentation Wrappers

	/**
	 * <p>
	 * Wrapper for getLink(String)
	 * </p>
	 * 
	 * @param name
	 *            Name given to local or global forward.
	 */
	public String link(String name) {
		return getLink(name);
	}

	/**
	 * <p>
	 * Wrapper for getMessage(String)
	 * </p>
	 * 
	 * @param key
	 *            Message key
	 */
	public String message(String key) {
		return getMessage(key);
	}

	/**
	 * <p>
	 * Wrapper for getMessage(String,Object[])
	 * </p>
	 * 
	 * @param key
	 *            Message key to be looked up and returned
	 * @param args
	 *            Replacement parameters for this message
	 */
	public String message(String key, Object[] args) {
		return getMessage(key, args);
	}

	/**
	 * <p>
	 * Wrapper for getAction(String)
	 * </p>
	 * 
	 * @param path
	 *            Name given to local or global forward.
	 */
	public String action(String path) {
		return getAction(path);
	}
}
